Ferro-aluminum alloy and method of making it



Patented June 25, 1929'. I 1,718,685

' UNITED STATES PATENT OFFICE.

RALPH n mum, on MENANns, AND HENRY ,A. :nE ERIEs, E ALBANY, NEw YORK,

AssIeNo s T0 LUDLUM STEEL ooMrAN 0E WATERVLIET, NEW YORK, A con-PoRATI'oN OF NEW JERsEY. v

FERBO-ALUMINUM ALLOY AND METHOD OF MAKING IT.

Ho Drawing. Application filed April 25, 1927. Serial No. 186,570.

Attemptshave been made heretofore to up to the desired 60%. Thisprocedure of make alloy steels containing substantial introducing thealuminum in two stages as amounts of aluminum; but great diflicultiesdescribed makes it feasible to introduce the areencountered,particularlywhen it is dedesired amount of aluminum without the diffi sired to havethe aluminum present in a defificulties which are otherwise experienced,as nite predetermined proportion. These difdescribed above. It isimportantthatneither ficulties arise from the fact that aluminum toomuch nor too little of the aluminum be has a lower melting point thaniron, is lighter used 111' the deoxidizing step. If the amount thaniron, and has great aflinity for oxygen. 1s either too large or toosmall a scum or to When aluminum is added to a molten bath dross willform consisting I principally of of steel, it will melt quickly, floaton the suraluminum oxide which will make impossible face, and rapidlyoxidize. An uncertain part the addition of the desired amount of alumifth l i ill th r f r pass ofi as num or its forming the desired alloy.The slag and in addition th ti f th formation of the dross or aluminumoxide 15 aluminum oxide may be held in the steel in h p f he bath oncestarted, its formaa finely divided state. This latter condition loncontinues progressively as the further is very objectionable and rendersthe steel aluminum is added. The production of a unfit for commercialuse. The impossibility fcrro-alummum of a definite chemical comof makingthe alloy to any definite specificaposltionwould under such conditionsbecome 20 tion in this way is obvious. The action of the IHIPOSSIblGJaluminum just described has resulted in its A typl al alloy produced byour method use as a deoxidizcr o preventive against \Vlt-lllll the rangedesired is 21S fOllOlVSf oxidation of molten steel, and its use has beenPer cent. restricted to this purpose. f f .055 r 535 By our method,described below, it be- Slhcon 0.58 comes possibleto obtain alloys ofaluminum Iron 45.23 and steel with the aluminum present in any Alumlnum54.00 so desired proportion within very narrow limh proportions of 40%iron and 60% a1umi and the p' p lment'lon may be num are based on thetheoretical formula to stated as the provis on of a method of pI'0- Al pd it ill b t d th t th iducmg such alloys: tion Whose analysis is givenapproximates Our invention is based on the fact dismi -1 1 covered by usthat the difliculties pointed out method f preparing this alloy iaboveare almost entirely absent if the alumi- Hates the loss f some zf t i bl35 T111111 is added to-the Steel bath in the tion of the aluminumthrough oxidation.

a l of composltlon which would make it impossible to make the as f yP05511319 of 111011 and alloy of anydefinite aluminum content; andaluminum. The difficulty fl also eliminates the danger of the inclusionor of mlkmg Such a y 0f h compoltlon occlusion in the finished productof any alumimentloned; and a Partof 01117 lllventlqn 15 h num oxidewhich would render the steel unfit new method next described of preparmgthis for uses we Want to put i to. 20450 alloy. This alloy ofsubstantially 40% steel and TolJrepal'e thls alloy of steel and 60%aluminum content is intended principalalumlnuln We Proceed as follows:ly for use in connection with the preparation t5 W? first melt steelscrap next to be described of alloys containing! any of sultablecomposltion. An electric furnace ll d i d proportion f l i m isconvenient for this purpose. Th molten though we do not wish to beunderstood as bath is then deoxidized by adding a small limitingourselves in this respect. amount of aluminum, onlyasuflicient amount We'have found that the addition to a 5U of this metal being added to forma very thin molten bath of steel of alloy'of the composi film of moltenaluminum on the surface of the tion indicated by the formula Al Fe, thatis, bath. Next suflicient molten or preheated of substantially 40% ironand 60% aluminum aluminum is added to bring the percentage content,results in a melting of this alloy and a uniform mixing of the aluminumcontent through the melt, Without its floating to the surface and thereoxidizing. The alloy, we have noticed, takes longer to melt, and thisslower melting may have something to do with the good results obtained.We have found that adding aluminum to the steel .in a combination ofiron and aluminum in almost any proportion probably gives better resultsthan adding the aluminum by itself; but the best results are obtainedwith the proportion of aluminum and iron described above. The results Iare markedly inferior when a departure from the proper proportion ofabout 7% plus or minus or more of either constituent is made. With analloy containing iron in percentages of 10 to 20 and the balancesubstantially aluminum, the advantage, if there is any, has become soslight as not to be noticeable.

We claim:

1. In the preparation of a ferro-a-luminum alloy the steps of meltingiron, adding a small amount of aluminum thereby deoxidizing the iron,and then adding sufficient aluminum to alloy the steps of melting iron,addin" just n h sufiiclent aluminum to form a thin film on the surface,and then adding sufiicient melted aluminum to bring the aluminum contentup to 60% of the initxure.

4. In the preparation of a ferro-aluminum alloy, the steps of meltingsome iron, adding a small amount of aluminum, thereby deoxidizing theiron, adding a suflicient amount of aluminum to bring the aluminumcontent up to 60% of the mixture, and adding such an amount of the alloyso formed to a batch of molten iron as will give the desired aluminumcontent to the resultant alloy.

RALPH P. DE VRIES. HENRY A. DE FRIES.

